I’m using cube orange plus with here 4 over my hexacopter. Most of the time my hexa showing an error “height estimate not stable “. After some time it vanished. Even in that error cube let me take off but I observed that if I takeoff when the error message showing then the aircraft not able to precisely maintain altitude.
Add logs, and at the very least write the PX4 version you’re using.
Even I am facing the same thing. I am using version 1.15.4.
Provide flight logs through PX4 Flight Review, otherwise we can’t diagnose your issue.
There are many causes but one could be wind over the flight controller from the propellers or excessive vibrations.